diff --git a/src/main/java/app/model/Model.java b/src/main/java/app/model/Model.java
index 850ce95..d88cbd1 100644
--- a/src/main/java/app/model/Model.java
+++ b/src/main/java/app/model/Model.java
@@ -15,8 +15,8 @@ import javafx.scene.Scene;
 public class Model {
   private static boolean fileIsSaved;
   private static Optional<Path> activeFilePath;
-  private static Optional<Path> currentProjectPath;
-  private static ProgrammingLanguage currentProgrammingLanguage;
+  private static Optional<Path> activeProjectPath;
+  private static ProgrammingLanguage activeProgrammingLanguage;
   private static String theme;
   private static Scene scene;
   private static SettingsProvider settings;
@@ -26,19 +26,23 @@ public class Model {
   }
 
   public static void setActiveFilePath(Optional<Path> path) {
+    if (path == null)
+      throw new IllegalArgumentException("path can not be null");
     Model.activeFilePath = path;
   }
 
   public static Optional<Path> getProjectPath() {
-    return currentProjectPath;
+    return activeProjectPath;
   }
 
   public static void setProjectPath(Optional<Path> path) {
-    Model.currentProjectPath = path;
+    if (path == null)
+      throw new IllegalArgumentException("path can not be null");
+    Model.activeProjectPath = path;
   }
 
   public static ProgrammingLanguage getLanguage() {
-    return currentProgrammingLanguage;
+    return activeProgrammingLanguage;
   }
 
   public static Scene getScene() {
@@ -58,14 +62,20 @@ public class Model {
   }
 
   public static void setTheme(String theme) {
+    if (theme == null)
+      throw new IllegalArgumentException("theme can not be null");
     Model.theme = theme;
   }
 
   public static void setLanguage(ProgrammingLanguage language) {
-    Model.currentProgrammingLanguage = language;
+    if (language == null)
+      throw new IllegalArgumentException("language can not be null");
+    Model.activeProgrammingLanguage = language;
   }
 
   public static void setScene(Scene scene) {
+    if (scene == null)
+      throw new IllegalArgumentException("scene can not be null");
     Model.scene = scene;
   }
 
@@ -74,6 +84,8 @@ public class Model {
   }
 
   public static void setSettingsProvider(SettingsProvider settings) {
+    if (settings == null)
+      throw new IllegalArgumentException("settings can not be null");
     Model.settings = settings;
   }
 
diff --git a/src/test/java/app/model/ModelTest.java b/src/test/java/app/model/ModelTest.java
new file mode 100644
index 0000000..6ec36ce
--- /dev/null
+++ b/src/test/java/app/model/ModelTest.java
@@ -0,0 +1,82 @@
+package app.model;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.mockito.Mockito.mock;
+
+import java.nio.file.Path;
+import java.util.Optional;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import app.settings.SettingsProvider;
+import javafx.scene.Scene;
+
+public class ModelTest {
+
+  @Test
+  @DisplayName("Test get/set fileIsSaved")
+  public void testFileIsSaved() {
+    boolean fileIsSaved = false;
+    Model.setFileIsSaved(fileIsSaved);
+    assertEquals(fileIsSaved, Model.getFileIsSaved());
+  }
+
+  @Test
+  @DisplayName("Test get/set activeFilePath")
+  public void testActiveFilePath() {
+    Optional<Path> activeFilePath = Optional.empty();
+    Model.setActiveFilePath(activeFilePath);
+    assertEquals(activeFilePath, Model.getActiveFilePath());
+    assertThrows(IllegalArgumentException.class, () -> Model.setActiveFilePath(null));
+  }
+
+  @Test
+  @DisplayName("Test get/set projectPath")
+  public void testActiveProjectPath() {
+    Optional<Path> projectPath = Optional.empty();
+    Model.setProjectPath(projectPath);
+    assertEquals(projectPath, Model.getProjectPath());
+    assertThrows(IllegalArgumentException.class, () -> Model.setProjectPath(null));
+  }
+
+  @Test
+  @DisplayName("Test get/set programmingLanguage")
+  public void testActiveProgrammingLanguage() {
+    ProgrammingLanguage lang = mock(ProgrammingLanguage.class);
+    Model.setLanguage(lang);
+    assertEquals(lang, Model.getLanguage());
+    assertThrows(IllegalArgumentException.class, () -> Model.setLanguage(null));
+  }
+
+
+  @Test
+  @DisplayName("Test get/set theme")
+  public void testTheme() {
+    String theme = "Monokai";
+    Model.setTheme(theme);
+    assertEquals(theme, Model.getTheme());
+    assertThrows(IllegalArgumentException.class, () -> Model.setTheme(null));
+  }
+
+  @Test
+  @DisplayName("Test get/set scene")
+  public void testScene() {
+    Scene scene = mock(Scene.class);
+
+    Model.setScene(scene);
+    assertEquals(scene, Model.getScene());
+    assertThrows(IllegalArgumentException.class, () -> Model.setScene(null));
+  }
+
+  @Test
+  @DisplayName("Test get/set settingsProvider")
+  public void testSettingsProvider() {
+    SettingsProvider settings = mock(SettingsProvider.class);
+    Model.setSettingsProvider(settings);
+    assertEquals(settings, Model.getSettingsProvider());
+    assertThrows(IllegalArgumentException.class, () -> Model.setSettingsProvider(null));
+  }
+
+}